Optical coherence tomography (OCT), a non-invasive medical imaging technology that uses non-ionizing radiation, has the potential to provide cellular level resolution in a system that is clinically viable, highly affordable, and portable. OCT is a recent development in medical imaging technology that has resulted in laboratory demonstrations of image resolution comparable to that of histology. However, due to the size, cost and unreliability of the laser source upon which these systems are based, they cannot be made to be clinically viable. This proposed NIH Phase I SBIR will result in the development of a fundamentally different laser technology that will enable a clinically viable OCT system capable of cellular level resolution to a depth of 0.5 mm in non-transparent tissue. During this program we will solve the key technical issues that currently preclude a clinically viable high resolution, high contrast OCT imaging system. The successful resolution of these technical issues will definitively demonstrate the feasibility of the proposed approach and will open up a new medical imaging modality. PROPOSED COMMERCIAL APPLICATION: In clinical studies being conducted at Wellman Laboratory of Photomedicine, OCT is providing real time images that are being used to guide excisional biopsies in the esophagus. By providing micron level guidance, OCT offers the potential for a dramatic reduction in sampling errors associated with blind biopsies. At higher resolution, OCT also holds the potential to eliminate the need for excisional biopsy altogether by providing the ability to perform an "optical biopsy". Optical biopsy could have important applications in dermatology, gastroenterology, cardiology, otolaryngology, dentistry, pulmonology, gynecology and urology.